Magnetic resonance imaging may be suited to so-called soft tissue imaging, since different types of tissue may be clearly distinguished within a patient, hence a high soft tissue contrast is present. Therefore, magnetic resonance imaging is frequently used to perform examinations in the region of the upper body of a patient, for example, abdomen and/or heart examinations.
A challenge that presents itself in the recording of magnetic resonance images in the region of the upper body is the breathing of the patient. If the target region to be imaged is moved by the breathing, movement artifacts, which make the resulting image quality much worse, may be produced as a result of the breathing. Thus, methods have already been proposed for avoiding or for reducing such movement artifacts.
In such cases on the one hand recording the magnetic resonance data during a breath-holding process of the patient is known, e.g., in a state in which the patient is holding their breath. To this end, it is known that breathing commands may be issued to the patient located within the bore of the magnetic resonance device, for example via special headphones or optically, wherein it is assumed that said patient will carry out these commands. Here, however, the cooperation of the patient must also be insured, wherein additionally it only becomes evident on viewing the reconstructed images whether the magnetic resonance data has actually been recorded in a breath-holding state, e.g., during a breath-holding process.
It has further been proposed to use a breath signal, (e.g., breathing information), to carry out the recording of the magnetic resonance data in a triggered fashion in specific sections of the breathing cycle. To establish the breath signal, there may be provision on the one hand for a so-called navigator, therefore a low-dimensional image recording of a contrast edge in the patient moving because of the breathing, (e.g., a restriction of the diaphragm), to be recorded and evaluated by the magnetic resonance imaging. It is also conceivable to use dedicated breath sensors, for example, a respiration belt, a chest belt, a breath sensor built into the patient couch, and the like. Breath information describing the current breathing state may be established both from navigators and also from the sensor data of a breath sensor, so that the recording of the magnetic resonance data or of a part of the magnetic resonance data in each case, may be triggered when the same breathing state is present, for example, during complete expiration. In relation to the use of navigators, an extremely complicated positioning of the navigator and a clear contrast is required, which isn't always ideal and easily possible. Sensors represent additional objects in the imaging region, (e.g., in the homogeneity volume), of the magnetic resonance device, e.g., further reduce the already small space in the bore and may possibly disrupt the recording of the magnetic resonance data.
Methods for movement correction of magnetic resonance data that may use such breathing information for example have also already been proposed, wherein the use of such methods is less preferred with the breathing information described, since this cannot describe the movement in the actual target region sufficiently accurately.